This invention relates to accurate placement of small elements such as required in lightwave component packages and devices and, in particular, to a transmitter, receiver, transceiver, or light switch including an optical fiber which must be aligned with a light source, detector, or another fiber.
In present lightwave transmitters, a light source such as a laser or light-emitting diode (LED) is usually provided within a hermetic package with the light coupled out of the package through an optical fiber aligned with the source. Similarly, lightwave receivers include a light detector, such as a PIN diode, which receibes light from the outside through an optical fiber aligned with the detector. Transceivers include both a source and detector. In all these packages, proper alignment is critical in view of the extremely small dimensions of the fibers. For example, a single mode laser and single mode fiber typically must be aligned to a fraction of a micron.
In the standard lightwave package, the fiber is aligned with the component and fixed in place by soldering. (See, e.g., U.S. Pat. No. 4,296,998, issued to Dufft.) Such a package provides high mechanical stability which is usually adequate for most applications. However, some uses require that the alignment be maintained for 10-20 years, and field installation, temperature variations, and long-term creep over such periods make it difficult to maintain such stability.
It is, therefore, an object of the invention to provide a lightwave package which is capable of maintaining optical fiber alignment over long periods of time.
In the case of optical switches, it is necessary to move an optical fiber aligned with another fiber or component into alignment with one or more additional fibers or components. Various mechanical means have been suggested for achieving such movement. (See, e.g., U.S. patent application W. C. Young, Ser. No. 432,254, filed Oct. 1, 1982.) Whiel adequate, it would be desirable to provide alternative optical switching means which have a lower cost and higher accuracy.
It is therefore a further object of the invention to provide a device for moving optical fibers into alignment with optical components, including other optical fibers, in order to provide an optical switching function. Furthermore, in the assembly of components, such as lightwave components, it is often necessary to provide for extremely accurate placement of piece parts. For example, piece parts for an optical connector must be placed within a holding fixture with submicron accuracy.
Therefore, it is a further object of the invention to provide a device for moving and positioning of parts with high accuracy.